Failed to load the patch object. Possible causes are:
The specified path is not an interim Patch shiphome
Meta-data files are missing from the patch area
Patch location = /software/oracle/product/GC10g/agent10g/inventory/oneoffs/5632264
Details = PatchObject constructor: Input file “/software/oracle/product/GC10g/agent10g/inventory/oneoffs/5632264/etc/config/actions” or “/software/oracle/product/GC10g/agent10g/inventory/oneoffs/5632264/etc/config/inventory” does not exist.

RollbackSession failed: PatchObject constructor: Input file “/software/oracle/product/GC10g/agent10g/inventory/oneoffs/5632264/etc/config/actions” or “/software/oracle/product/GC10g/agent10g/inventory/oneoffs/5632264/etc/config/inventory” does not exist.
System intact, OPatch will not attempt to restore the system

But: the files are there , and with the extension .xml ! Renamed the files , deleted the extension, performed the rollback again: no problem.